地下車站風壓量測

UNDERGROUND MRT STATION WIND PRESSURE MEASUREMENT

本研究針對機場捷運A7體育大學站，以實場監測方式獲得捷運地下車站全罩式月臺門的實際環境風壓值。累積足夠的樣本數量後，探討直達車進站時，風壓的平均值與標準差。根據極值分析與風壓統計值的特性建立20年迴歸期對應的目標風壓值。隨後，比對風壓的實際量測值與初始設計的數值模擬結果，以驗證實際量測值的正確性，並探討兩者差異的原因。本研究結果顯示：在月臺前端，模擬值正壓、負壓，分別高過及低於實測最大、最小值；於月臺中央，模擬值之正壓、負壓，皆低於實測最大、最小值；在月臺尾端，模擬值之正壓低於實測最大值，但負壓高過實測最小值。綜觀整個月臺，數值模擬與實場量測推估的正壓與負壓極值誤差分別為19%與0.2%，顯示兩者具有一致性。此外，利用應變規量測玻璃帷幕在風壓作用下產生的應變，比對有限元素模擬結果，得到應變大小與風壓變化具一致性。其次，直達車通過所引致的短延時脈衝風壓可直接取極值進行靜力分析，因為風壓變化的延時遠大於月臺門的基本振動週期，因此可以忽略動力效應。

This study examines the real-time monitoring at the National Taiwan Sports University Station (A7) to acquire actual environmental wind pressure values for the full-height platform screen doors of the underground metro station in the Taoyuan Airport MRT system. After gathering enough samples, the study analyzes the mean and standard deviation of wind pressure when express trains pass the station. Based on the extreme value analyses and statistical characteristics of wind pressure, the target wind pressure values for a 20-year return period were established. The in-situ measured wind pressures were compared to the numerical simulation results to verify the accuracy of the measurements. Our results indicate that at the front of the platform, the peak positive and negative pressures from the numerical simulation were, respectively, higher and lower, than those from the in-situ measurements. At the center of the platform, the maximum positive and negative pressures from the numerical simulation were lower than those from the in-situ measurements. At the rear of the platform, the peak positive pressure from the simulation was lower than the in-situ measurement, while the peak negative pressure was higher than the in-situ measurement. Overall, the estimated extreme value errors for positive and negative pressures between numerical simulations and field measurements were 19% and 0.2%, respectively, demonstrating an agreement between the two methods. In addition, strain gauges were used to measure the strain induced in the glass curtain wall under wind pressure, and the results were compared to finite element simulations. The magnitude of the strain was found to be consistent with the wind pressure. Moreover, the short duration impulsive wind pressure caused by passing express trains can directly take the extreme value for static analysis. Since the duration of wind pressure variations is significantly longer than the platform doors’fundamental vibration period, dynamic effects can be disregarded.